1. Field of the Invention
The present invention relates to a fuzzy control system, a rule-based control system which controls a to-be-controlled object whose dynamic characteristics characteristic are not sufficiently understood or which vary during operation (e.g., a plant, robot, etc.), thus making the application of conventional theory difficult. The system uses control rules of a skilled operator or an expert.
2. Description of the Related Art
A fuzzy control system is a rule-based control system which is characterized by expressing control rules of an expert using a fuzzy theory and determining a control command by a fuzzy inference.
A conventional fuzzy control system performs control based on standardized control rules to directly acquire a control value from the status of a to-be-controlled object, so that an output identical to an input value is always produced. The conventional fuzzy control system cannot therefore achieve adaptive control which reflects an expert's global judgment on the status of a to-be-controlled object for determining a control command; for example, based on an object state judging rule such as "if the pressure is high and a change in water level is positive, the condition of the to-be-controlled object is not good" and a control rule such as "if the state of the to-be-controlled object is good and the pressure is high, then open a governing valve slightly." That is, conventionally, the high-grade or sensitive judging function of an expert cannot be reflected in the control of the to-be-controlled object.